[lug] Very odd, not really linux question -- WATT 32, AT&T at home

[John Karns]

On Sun, 18 Nov 2001, Brad Grissom said:

> Not completely related to this, but I also have @home.  My problem is
> how do I see other machines on the home network?  We each have our
> little c338829-a.lakwod3.co.home.com addresses, but I need to know the
> internal network stuff.
>
> I guess it would help to know what I am trying to do.  I am trying to
> scp some files onto the Windows machine, from the Linux machine.
> Basically I have pscp on the Windows machine (Putty's SCP) and I am
> copying stuff from the DOS prompt.  I can do something like:

> pscp grizzyb at 24.182.228.14:/home/grizzyb/file C:\file
>
> or
>
> pscp grizzyb at c338829-a.lakwod3.co.home.com:/home/grizzyb/file C:\file
>
> But each of those go through the @home servers and limit the
> bandwidth.  I just want to identify the Linux machine as 192.168.0.12
> or whatever but I haven't figured out how.  Nothing sees anything else
> on the home network!

It sounds like all your IP@'s are valid Internet IP@'s.  The idea would be
to create an isolated private net.

I think there are two alternatives.  BTW, to find out what addresses your
W machines are using -> Start / Run / winipcfg


1) Your cable modem is a router with NAT DHCP capability:

then after setting it up for NAT / DHCP via it's configuration mechanism,
it would assign private IP@'s to all machines.  In this scneario, only the
router would have an Internet IP@ assigned by @home.

2) If your cable modem isn't of that type:

then in order to isolate your W machines, you would add a hub / switch for
your private net, and set up the Linux box to do NAT (there are various
HOWTO's describing this - see the LDP sites, or consult your Linux distro
many include most of them).  In this scenario, only the Linux machine
would have an IP@ assigned by @home.

You could then assign a 2nd IP@ to the Linux eth interface via IP aliasing
- I've never tried it, but seen it in the kernel configuration.  To do
this, your kernel would have to be compiled to support this.  For example,
if your W machines have something like:

192.168.1.10
192.168.1.11

then assign something like IP@ of 192.168.1.9 as an aliased IP.

Alternatively, you could install a 2nd NIC in the Linux box and avoid the
IP aliasing - this would probably be the best way (NIC are cheap!).

This would allow communications between your machines without traversing
the line back to the ISP for your routing.

HTH

----------------------------------------------------------------
John Karns                                        jkarns at csd.net